Woker channel for parallel processing of async function

channel.js

class Channel {
  _results = [];
  _index = 0;
  constructor(list = []) {
    this._list = list;
  }

  push(...items) {
    this._list.push(...items);
  }

  clear() {
    this._results = [];
    this._index = 0;
    this._list = [];
  }

  get results() {
    return this._results;
  }

  next() {
    if(this._list.length === 0 ) {
      return [false];
    }
    const item = this._list.shift();
    const cb = this._callback(this._index)
    return [true, [ item, this._index++ ], cb]
  }

  _callback(index) {
    return result => {
      this._results[index] = result;
    }
  }
}